Ralph pulled up suddenly and began to speak. "I brought you here to-night, Geoffrey," he said, "so that you might have the first lesson in the task that lies before you. Listen! can you hear anything?" "I hear the roar of the sea, the waves grating on the shingle." "Yes, because we are on a level with the sea. There are deeper vaults yet, which you will see presently, and they are below the level of the sea. Our ancestors used to place their prisoners there, and, by removing a kind of sluice, allowed the tide to come in and drown them. You see, those walls are damp." They were, indeed. As a wax vesta flared up, the dripping stones and the long white fungi gave the place a weird appearance. Then Ralph dropped suddenly, extinguished his match, and drew his companions behind a row of cupboard-like timbers. "Somebody is coming," he whispered. The others could hear nothing. But the blind man's powers of hearing were abnormal. It seemed a long time before the sound of footsteps could be heard. Then a figure in white, a fair figure with long shining hair hanging down her back and carrying a taper, crept down the steps. An exclamation trembled on Geoffrey's lips--an exclamation of alarm, of admiration, of the utmost astonishment. But Ralph laid a hand on his mouth. The figure passed into the vault beyond. "It was Marion!" said Geoffrey in a thrilling whisper. "And yet it did not look like Marion. She seemed so dreamy; so far off." "She was walking in her sleep," Ralph said quietly. "But the danger of it, the danger!" "My dear boy, there is no danger at all. Blind as I am, I found out this peculiarity of Marion's directly I returned. Danger to her! I would not have a hair of her head injured to save Ravenspur from destruction. Geoffrey, it is through Marion and Marion alone, that we are going to solve the mystery." "Ay," Tchigorsky muttered, "that is so." Ralph raised his hand to impose silence. The soft returning footfalls were clear to the ears. Then, rigid, unbending, with dilated eyes, Marion passed, the flash of the lantern behind her. "Come," said Ralph, "let us return. A good night's work, Tchigorsky!" "Ay," Tchigorsky murmured; "a good night's work, indeed." CHAPTER XIII REELING OFF THE THREAD It was fortunate for all parties that Geoffrey was possessed of strong nerves, or he would have been certain to betray himself and them. Since he had left school at the time when the unseen terror first began to oppress Ravenspur, he had known nothing of the world; he had learnt nothing beyond the power to suffer silently and the power of love. To confide in him was, perhaps, a daring thing on the part of Ralph Ravenspur. But, then, Ralph knew his world only too deeply and too well, and he rarely made a mistake in a man. All the same, he followed as closely as possible the meeting between Marion and Geoffrey the following morning.